Energy distributions of neutral atoms and molecules sputtered from polycrystalline silver

Energy analysis by a retarding field method and mass spectroscopy of post-ionized sputtered neutrals have been combined to determine the energy distribution of neutral Ag1 and Ag2 particles sputtered by normally incident Ar+ ions of 1 keV. A hf-plasma at an Ar pressure below 10-3 torr has been used for the ion bombardment of the target and simultaneously for electron impact post-ionization of sputtered neutral Ag2 molecules ejected perpendicular to the target surface is shifted to smaller ejection energies compared with the corresponding results for Ag1. The behaviour is discussed in view of a statistical model for molecule formation in low energy sputtering. (Auth.)